How can you automate the verification of any actions in real life?

Question

augmented reality

Task: to automatically check whether the user of the service has really done some action in the real world.
That is, for example, location verification can be organized through check-ins in foursquare (or your own mobile software). What about other actions?
One of the options that came to mind is uploading a photo with confirmation of completion, perhaps.
But if you need to confirm a lot of monotonous actions, it will be problematic.
Another way is pieces of paper with codes, as in encounters / patrols / fights. Here the minus is that these pieces of paper must be hidden in advance. And how to check the task "hide a piece of paper with a code"?
Maybe I'm trying to reinvent the wheel and already have something ready?
ps in the ideal case, the method should work with any offline action, but limited options are possible. Naturally, it means that all checks are with the permission of the user.

Answer 1

Funny question. Here after all understand a question in the price. If you are willing to pay, then you can also get a GPS. If not ready, then RFID or pictures of barcodes against each other.

Answer 2

Geocaching

Answer 3

Solder a small device with a GSM chip and a button. When the button is clicked, make an HTTP request to the server. Well, of course, each device has its own unique code.
If you need to determine who exactly clicked, you can catch the coordinates of all people via GPS (using an application on your phone, for example) and compare the coordinates of people and the device turned on. Or add buttons to the device so that each person enters their own code.

Answer 4

Well… maybe then Motion capture can be used…

Answer 5

Most suitable is the set of measures proposed above folded into one application for the phone.